Maybe you have such question as why NProxy when we have Fiddler, Charles, Rythem and Tinyproxy. Yes, there is no doubt that they are all great tools, however they don't meet my requirements:

Support Mac, Linux and Windows(especially Mac and Linux)

Support replacing combo files with separated source files

Support directory mapping

This is the main reason why NProxy is here. Besides, NProxy can improve the efficiency of my daily development for enterprise-level product with a bunch of complex building processes, which cost me lots of time.